Over the last few decades revolutionary advances have been made in electrochemical storage and conversion devices expanding the capabilities of these systems in a variety of fields including portable electronic devices, air and space craft technologies, passenger vehicles and biomedical instrumentation. Current state of the art electrochemical storage and conversion devices have designs and performance attributes that are specifically engineered to provide compatibility with a diverse range of application requirements and operating environments. For example, advanced electrochemical storage systems have been developed spanning the range from high energy density batteries exhibiting very low self-discharge rates and high discharge reliability for implanted medical devices to inexpensive, light weight rechargeable batteries providing long runtimes for a wide range of portable electronic devices to high capacity batteries for military and aerospace applications capable of providing extremely high discharge rates over short time periods.
Despite the development and widespread adoption of this diverse suite of advanced electrochemical storage and conversion systems, significant pressure continues to stimulate research to expand the functionality of these systems, thereby enabling an even wider range of device applications. Large growth in the demand for high power portable electronic products, for example, has created enormous interest in developing safe, light weight primary and secondary batteries providing higher energy densities. In addition, the demand for miniaturization in the field of consumer electronics and instrumentation continues to stimulate research into novel design and material strategies for reducing the sizes, masses and form factors of high performance batteries. Further, continued development in the fields of electric vehicles and aerospace engineering has also created a need for mechanically robust, high reliability, high energy density and high power density batteries capable of good device performance in a useful range of operating environments.
Many recent advances in electrochemical storage and conversion technology are directly attributable to discovery and integration of new materials for battery components. Lithium battery technology, for example, continues to rapidly develop, at least in part, due to the discovery of novel electrode and electrolyte materials for these systems. The element lithium has a unique combination of properties that make it attractive for use in an electrochemical cell. First, it is the lightest metal in the periodic table having an atomic mass of 6.94 AMU. Second, lithium has a very low electrochemical oxidation/reduction potential (i.e., −3.045 V vs. NHE (normal hydrogen reference electrode)). This unique combination of properties enables lithium based electrochemical cells to have very high specific capacities. State of the art lithium ion secondary batteries provide excellent charge-discharge characteristics, and thus, have also been widely adopted as power sources in portable electronic devices, such as cellular telephones and portable computers. U.S. Pat. Nos. 6,852,446, 6,306,540, 6,489,055, and “Lithium Batteries Science and Technology” edited by Gholam-Abbas Nazri and Gianfranceo Pistoia, Kluer Academic Publishers, 2004, are directed to lithium and lithium ion battery systems which are hereby incorporated by reference in their entireties.
Advances in electrode structure and geometry have also recently developed. For example, U.S. Patent Application Publication US 2011/0171518 (Dunn) and International Patent Application publication WO 2010/007579 (Verhaegh) disclose three-dimensional battery structure for solid-state lithium ion batteries. U.S. patent application Ser. No. 7,553,584 and U.S. Patent Application Publication US 2003/0099884 (Chiang) disclose batteries in which the electrodes are formed as complementary structures. U.S. Patent Application Publications US 2012/0077095 and 2013/018959 (Roumi) describe three-dimensional electrode structures. Japanese Patent Application Publication 2006-286427 describes electrode plates containing an internal conductive layer; conduction passages between the internal conductive layer and the charge collector are also shown.